Is the sound of the mic when is in front of a speaker that is connected to the mic. During the record I moved the mic to obtain different effects.// Sonido de acople de un micro. Durante la grabación movía el micro frente al altavoz para obtener diferentes sonidos.

Very annoying, but that's a good thing! Duplicate it, stretch it a bit, and change the pitch by a semitone, then play it back with the original and you've got a real ear-bleeding effect (which is what I was after).